Studies of microstructurally small fatigue cracks have illustrated that heterogeneous microstructural features such as inclusions, pores, the grain size distribution, and the  precipitate size distribution and volume fraction create stochasticity in their behavior under cyclic loads. Therefore, to enhance safe-life and damage-tolerance approaches, accurate modeling of the influence of these heterogeneous microstructural features on microstructural small crack formation and growth from stress raisers is necessary. In this work, computational micromechanics is used to predict high cycle fatigue of microstructurally small crack formation and growth in notched polycrystalline nickel-base superalloys and to quantify the variability in the driving force for formation and growth of microstructurally small crack from notch root in the matrix with non-metallic inclusions. The framework involves computational modeling to obtain three-dimensional perspectives of microstructural features influencing fatigue crack growth in notched polycrystalline nickel-base superalloys. The simulation results obtained using this framework is validated using experimental results for polycrystalline nickel-base superalloys.

microstructurally small crack, crystal plasticity, nickel-base superalloy, fatigue life.